Multistage gear controlling mechanisms have as a rule a considerable structural length, which for example is determined by the number of the gears which are arranged side-by-side on the gear shafts and the length of the shifting path. It is therefore necessary to support the gear shafts several times, for example between two adjacent gears or gear blocks. For this purpose the gear housings as a rule have several walls which form the bearing points for the gear shafts.
In known gearing mechanisms of the mentioned type, these walls are constructed for example in one piece with the closed or also divided gear housing. The working of the shaft passages in these walls is very complicated because of the great working depth and requires special working machines. In many cases, the gear housings include heavy columns, spindle sockets or the like, the handling of which and setting of which for the purpose of working is very complicated.
A further disadvantage of gear housings of the known type is seen in that, for example in the case of a faulty working of the walls, the entire gear housing or the entire next larger structural unit, with which same is to be integrated, becomes scrap and that in the case of a repair of the gearing this entire structural unit is blocked for the time of the repair.
Therefore, so-called slide-in gearings have already become known, in which a kind of a cage, consisting of the support walls and connecting and closing-off walls, is mounted together with the gear shafts and operating devices and is installed as a unit into the gear housing, which as a rule contains then also the lubricant trough. Thus the working problem and the repair problem are reduced, because the slide-in gearing unit offers a smaller, quickly exchangeable structural unit. At the same time, however, the disadvantage exists that the space needed for a complete slide-in gearing is greater than the space needed for installation of the gear parts directly into the gear housing. Furthermore to mount the slide-on gearing, again worked surfaces must be provided in the gear housing, so that a part of the aforedescribed problems remain in existence.
The purpose of the present invention is to produce a gearing unit of the abovementioned type, which is simple in structure and is thus simple and inexpensive to manufacture and install, and which requires little space.
This purpose is inventively achieved by the walls being constructed as individual support plates which can be inserted into the gear housing, which support plates can be fixed by means of index bolts or the like which are supported in the housing wall and extend from outside radially into the peripheral surfaces of the plates.
The support plates have preferably a small radial play with respect to the gear housing. Same can remain unworked on the inside, because the support plates are aligned and fixed by the index bolts and do not need to come into contact with the inner wall of the housing. For this reason, the inner cross-sectional shape of the gear housing is very freely selectable, because same is not predetermined by any kind of working requirements, for example the requirement that a working is supplied to take place by boring or turning.
Working of the support plates is very simple and can for example be made easier yet by clamping same together to a block and by working same like a workpiece.
The installation of the gearing unit can be done in such a manner that the support plates are mounted together with the gear shafts carrying the gears in a mounting device and are moved as a unit into the gear housing, where then the support plates are aligned exactly and fixed by the index bolts. The demounting takes place in a reversed manner.
An important advantage of the inventive solution is seen also in the gearing being able to be installed for example in a pipe-shaped housing without lateral openings which is, from the viewpoint of bending and torsion rigidity, the optimum solution.
According to a further characteristic of the invention, the index bolts can be placed from outside through through holes in the housing wall so that also the manufacture of said holes in the housing can be done from outside.
To lubricate the gearing inside the housing, the invention provides that the individual support plates are provided with channels which can be connected to a lubricant supply and which extend to bearing points. Tubes or the like can branch off from these channels, which lines supply the gears with lubricant.
A technically easy mounting solution results when the supply of the lubricant to the support plates is done from outside of the gear housing through the housing wall, so that inside of the gear housing a pipe line system does not need to be installed.